I try to get her to concentrate on me and reasure her ,Big no on the reaasurance
Does she growl if someone strokes/touches her away from the table ? If she does she obviouslly has bigger problems
TBH I would get someone you trust to go over your bitch silently & without eye contact & they should give her a treat if she doesn't grumble. I don't mean like a judge but simply running their hands over her at first without touching her at all & if she doesn't growl then very very gently with almost no contact. If you have someone else she trusts they could present her on the table for you.I wouldn't bother re getting her to stand perfectly just for her to be still & not stressed.
It can be a learned behaviour she finds the touching stops it she growls so she growls to stop the touching
I would also do some
T Touch massage with her not only will it relax her but it will also get her used to being handled & it being enjoyable